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bnjmnp / pysoem

Cython wrapper for the Simple Open EtherCAT Master Library
MIT License
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No connection to EtherCat slave #75

Open zlymudzyn opened 2 years ago

zlymudzyn commented 2 years ago

Hi,

I have quite an odd problem: I am trying to connect to a slave via EtherCAT using pysoem. When I am directly connected to the device, everything works fine. Problem occurs when I am trying to connect to it via Netgear managed switch. Then, the device is not visible at all. I've tried using a program Codesys, which is also able to simulate an EtherCAT master and, to my surprise, it is able to find the slave and connection works fine.

Using pysoem I am using the minimal_example.py file and it does not find anything. I am running it on Raspbian.

What could be causing the problem here? I would rather use pysoem than Codesys, as it gives me way more possibilities.

bnjmnp commented 2 years ago

As far as I know managed switches should not be put into an EtherCAT network. Almost all EtherCAT devices have an in and out port, so you connect them one after the other (https://www.ethercat.org/en/technology.html#1.3. If your devices only have on port you need an "EtherCAT switch" like the Beckhoff CU1128.

zlymudzyn commented 2 years ago

The problem is that the device I am testing has multiple protocols that it can communicate through: Profinet, Ethernet IP, Ethercat. Therefore I would rather not use a dedicated EtherCAT switch as it would mean I would need a separate test bench for testing EtherCAT only. Doable, just not preferable.

The device I am testing has one communication port for all these protocols. There is a switch inside of it.

From what I can understand EtherCAT can be used with with this managed switch, as Codesys finds the device as EtherCAT slave no problem(I have created a separate VLAN for my raspberry and the device), but using pysoem it does not find the device and I find it hard to understand why that might happen.

Using unmanaged switch it also works, but due to some limiting factors I cannot use it in my project. Any ideas?

bnjmnp commented 2 years ago

Not really. You could use Wireshark to see what Codesys is doing different. You may also go through the issues of the SOEM project itself, this is what PySOEM is based on. With a bit of luck you will find there the information you are looking for. Or ask for help there.